Igniting apparatus for gas-engines.



E. THOMSON.

IGNITI NG APPARATUS FOR GAS ENGINES. APPLIOATION FILED 1123.5, 1906.

1,021,21 9. Patented Mar. 26, 1912.

2 SHEETSSHBET 1.

* fihu Thomson M/Aa; I Atty E. THOMSON. IGNITING APPARATUS FOR GASENGINES.

APPLICATION PILEDAPILB, 1906. 1,021,219.

2 SHEETS-SHEET 2.

Witness es.-

- //71 ent0/1- A EL/hu Thomson y Atty.

Patented Mar. 26, 1912.

UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

IGNITING APPARATUS FOR GAS-ENGINES.

Specification of Letters Patent.

. Patented Mar. 26, 1912.

Application filed April 5, 1906. Serial No. 319,034.

To all whom it may concern:

Be it known that I, ELIIIU THOMSON,

a citizen of the United States, residing at I This invention relates. toimproved means for producing spark ignition of gasolene,

, gas and oil eng1nes and emhodiesvarious novel arrangements of a dynamoand the other parts of the system whereby the ign .tion is reliable, andfurthermore, can be timed to suit the speed of the gas or other enginewithout the employment of hand levers or other omplicated mechanism suchas is commonly used to eifect this result. The details of my inventionwill be better understood by reference to the following descriptiontaken in connection with the drawing forming a part of thisspecification.

,. Figure 1 is an elevation of my improved form of dynamo; Fig. 2 is anend elevation of the same; Figs. 3, 4, and 6 are diagrams showing thepolar pro ections of the dynamo represented in Fig. 1, and illustratingvariouspositionsof the rotating element of the dynamo with respect tothese polar pro-' jections; Fig. 7 is a perspective view of a polarprojection; Fig. 8 is a perspective view of the rotating element of thedynamo; Fig. 9 is a representation of the pressure wave generated by thedynamo; Fig. 10 shows one means for applying my improved form of dynamoto a gas engine to produce ignition of the charge in the enginecylinder; Fig. 11 shows my improved system as applied to a two cylinderengine and equipped with a selective distributor for automaticallydelivering current to the respective cylinders at proper time intervals;Fig. 12 shows asystem in which the two coils of the dynamo are connectedin series through a timing device to the low potential winding of atransformer; the high potential winding of which is connected directlyto the twocontacts of the spark plug; Fig. 13 represents a similarsystem with the two dynamo coils in parallel; Fig. 14; represents asystem applicable toa two-cylinder engine in which the two coils of thedynamo supply two separate spark plugs through separate transformers.

The dynamo represented in Figs. 1 and 2 comprises a plurality ofpermanent magnets 1 and 2 arranged in the same plane and with thin likepoles presented toward each other.- The poles are magnetically bridgedby laminated polar projections 3 and 4, on which are mounted thegenerating coils. 5 and (5. One of these polar projections is clearlyshown in perspective in Fig. .7 and embodies a central portion 15 onwhich the generating coil is wound. Two protruding pole tips 11 and13extend outward beyond the coil. I prefer to make these polarprojections 3 and 4 of considerable length, and subject them not only tothe magnetic flux from the magnets 1 and 2, but also to that-of otherpairs of' similar magnets arranged side by side along the polarprojections, as shown in Fig.- 2, in which the magnets 7, 8 and 9correspond in all respects to the magnet 2, and cooperate with othermagnets arranged on the opposite side of the polar projections. Therotor or movabl element 10 ofthis dynamo is shown in perspective in Fig.8, and consists merely of a shaft carrying a plurality of ironlaminations arranged one above another and secured to the shaft. Thisrotor when set in motion between the polar projections 3 and4 produces achange in direction of the magnetic flux threading the coils 5 and 6,and thereby nets, and the projection 4 is in contact with thecorresponding south poles or the same magnets so that a verticalmagnetic flux is established through the space in which the rotaryelement 10 lies. When the rotor is in the position shown in Fig. 3, themagnetic flux will thread through it from the pole tip 11 to the poletip 12, and very little 20 a flux is about to shift back to the pole tip11,

assuming a left-handq-otation. The peculma netic flux will pass throughthe tips 13 an 14. When the rotorassumes the position shown in Fig. 4the main flux will traverse the tips 18 and let and very little willpass through the other pole tips. As-

suming a left hand rotation-for the rotor,.

Fig. 5 shows its position midway between the two positions illustratedin-Figs. 3 and Y 4, which position is. approximately that at which themagnetic flux shifts from the pole tip 11 to the pole tip 13, and bysodoing cuts through the coil normally mounted on the narrow connectingpiece 15. ,By making the rotor of considerable length I am able to makethis shifting over of the magnetic flux very abrupt, and as aconsequence I am able to secure a pressure wave having a very sharp peakat the maximum point,

as shown diagrammatically in Fig: 9.. Fig. 6 shows the secondmid-position when the iarities of design and operation embodied inthedynamo above described give the peculiar wave form shown in Fig. 9, andthe height of the positive and negative peaksis determined by thespeedof rotation of'the element 10 and the number of turns in the coils5 and 6; so that by varying either or bothof these factors I can secure"any va' riation in the maximum value of the pressure wave within verywide limits. I find that-by making the coils 5 and 6 of manycomparatively small numberof turns, and

to interpose'a-transformer between the dy-- namo andQthe-spark plugs.Such a system is shown diagrammatically in Fig; 10 in which the dynamo16 is shown connected I permanently to the: terminals,of the transformer primary 17,- thereby supplying energy to the high potential coil18 of the transformer which has one. terminal grounded to the frame of.the engine 19, and the other terminal connected to a rotating selector20 which operates to deliver current to a receiving shoe 21 at theproper t1me interval, so that when the current umps from one electrodeof .the spark plug 22 to the other electrode, and thence re-.

' turns through the frame to thetransformer, the spark so produced willoccur justat the t1me the explosive charge in the engine cylinder isready for i ition. The'rotating contact finger 20 is rigidly connectedto. the

- gear wheel 23meshing with the gear 24 cartion of the engine.

ried by the gas engine, these two gears having such diameters that thecontact hnger 20 makes one rotation to every two oi the gas engineshaft, and consequently pro-- duces an igniting spark every secondrevoludriven in any suitable manner, as by a belt 25 driven by apulleyon the gas engine axle. The continuous rotation of the dynamo l6develops a continuous series -of peaked waves in the transformersecondary 18, though these pressure waves are utilized only during thebrief interval when the The dynamo 16 may be 7 selector 20 is inproximity to the receiving shoe 21. If desired, the electrical circuitbetween the members 20 and 21. may be completed by mechanical contact,but I prefer to separatethe parts sufliciently to prevent such contact,and to rely on theelectromm tive force of the electrical energy to breakdown this gap and establish electrical connection'through'the spark soformed. This arrangement obviates entirely the mechanical wear of ,onepart on another, and fur; thermorc provides means for the automaticadvance, of the spark as the engine speed increases, this eii'ect beingproduced in part by the increase in dynamo voltage as the speed goes up,and in part by the curved the position corresponding to the minimumdistance bet-Weenthetwoelements and will therefore give an automaticadvance of the spark directly proportional to the increase in speed; Bycurving the receiving shoe 21 awayirom the arc of the rotating linger20, I can secure any desired I relation between the speed and the sparkadvance.

shape of the receiving shoe 21, for it will be readilyunderstoodthat asthe voltagegoes up, the current will ump to the contact shoe before, therevolving selector 20 reaches 1 05 By using a belt drive between thedynamo 16 and the gasengine I am able to secure a speed much highemthanthat of the engine, and in fact so high that each spark discharge .inthe engine cylinder may embody .fseveral complete cyclesof the dynamo"current. Maximum speeds as high as three thousand revolutions per minutemay be used, as the revolving element is small and consists merely ofiron laminatio'ns without windings of any sort-thereon. This method ofconnecting the dynamo to the gas engine obviates the necessity forsynchronous speeds betweenthe two, and thus makes it possible to removethe dynamo from the-engine frame for repairs and to return it to itsposit-ion without danger of disarranging the phase relationbetween thedynamo cur-p rent and the engine piston, this difiiculty" being onecommonly; experienced with geared igniters. The high speed makes it Ipossible to obtain a'ma-ximum voltage from. the dynamo coils and'in factwith a fine.

' on the speed of the gas engine. VVhile- I shoe 29 to secure the exactrelation desired of the 'spark transformer to raise the voltage of thedyto the one shown in Fig. 10, except that it revolvingfinger 31approaches the receivits pivotal sup ort 32, thereby increasing primary34 and a selector distributer 35.

Winding for the generator coils I am able'l to deliver a sharp hot sparktothe spark plug of the engine without theme of a Iiaino. The fact thateach discharge at the spark plug embodies several complete cycles ofcurrent makes unnecessary any adjustment in position of the dynamo fieldto compensate for the time advance in the spark as is common practicewhen the dynamo runs in synchronism with the gas engine, this adjustmentbeing necessary tocompleting the circuit at the instant when thepressure wave is very low, for in such cases the voltage might not besufficient to generate a spark'to' ignite the engine charge.

Fig. 11. shows my improved system applied to a two-cylinder enginerepresented by the two spark plugs 26 and 27, which alternately receivecurrent from the selector distributer 28. This distributer is similarincludes two receiving shoes 29 and 30 by which the charges are led tothe two spark plugs. This distributor embodies the feature of automaticadvance 'described in connection with distributer 20, for when the ingshoe 29, the -electrical discharge will jump across the intervening gapand the distance jumped will depend on the voltage. of the dynamo whichin turn is dependent contemplate.adjusting'the curve of contact betweenspeed and advance of the spark,

thereafter dep'endingentirely on the automatic action of the device, itwill be under-, stood that other adjustments may be made, if desired, byshifting the shoe 29 about the minimum dlstance of the spark gap andalso readjusting the other distances through which the spark must jumpas the engine speeds up. v

Although I have shown only tWo spark plugs to represent a two-cylinderengine it will be understood that the system is equally applicable tofour-cylinder engines by merely adding other receiving shoesaround thearc of the rotating selector 31. If desired I may dispense with thetransformer 33 and connect the dynamo directly across the circuit.

Fig. 12 is a diagram of the connections of the dynamo showing the twocoils 5 and 6 connected in series through a transformer The highpotential transformer winding 36 isconnected directly tothe twoterminals plug 37. This arrangement simplifies the ighpotential circuitas all interruptions of current take place at the secure by LettersPatent of the United States, is,"

1. The combination with an explosive engine, of sparking terminals forigniting the explosive charge of said engine, means for developingelectrical energy for supplying said sparking terminals, and means forde termining the instant at which said energy is delivered to saidterminals and for automatically advancing the discharge with respect tothe engine piston as the speed of the engine increases including arotating arm and a receiving shoe, said shoe beng curved away from thearc of the rotating arm.

2. .The combination of an explosive en-- gine, a dynamo for developingenergy to explode the charge of said engine, and automatic means foradvancing the time of explosion as the speed of the engine increasesincluding a rotating arm'and a movable receiving shoe, said shoe beingcurved away from the arc of the rotating arm and at a sparking'distancetherefrom 3. In an igniting system for explosive engines, a currentdistributor comprising a 1'0- tating arm, a receiving shoe at a sparkingdistance from said rotating arm out out of contact therewith, and acircuit including a spark plug and a source of power connecting saidrotating arm with said receiving shoe, said receiving sho'e being curvedaway from the arc of the rotating arm as to automatically advance thedischarge with respect to the engine piston as the speed of the engineincreases. i

4. The combination with a inulti-cylinder engine, of a plurality ofspark plugs therefor, a receiving shoe connected with each spark plug, arotating arm movable to a sparking distance from each of said receivingshoes, and a source of electrical energy for causing current to jumpfrom said rotating arm to each of said shoes successlon, said receivingshoes beingcurved away" respect to the engine piston as the speed of,

the engine increases.

.' 5. The'combination with an explosive engine, of a source ofelectrical energy delivering a peaked current wave, and a circuitconnected therewith including a spark plug, 'In witnees whereof, I havehereunto set erotatmg arm and a recelvmg shoe at a my hand thlssecond-day of Aprll, 1906. sparklng dlstance awayfrom szud arm, sald'shoe being eurved'awhy from the are of the ELIHU THOMSON.

rotating arm so' as to automatically advance itnessesz the dischargewith respect to the engine pis- JOHN A. MCMANUS, J r.,

ton as the speed of the engine increases. v PHILIP F. HARRINGTON.

Capies of this patent may be obtained for five cents each, by addressingthe Commissioner of-Patents.

Washington, I). C.

